The present invention relates generally to equipment for charging electric storage batteries and more particularly to apparatus for formation charging wet electrical storage batteries.
Formation is a step in the construction of lead acid electric storage batteries wherein the active materials of the cell, that is sponge lead on the negative plates and lead peroxide on the positive plates are created. This can be accomplished by mounting positive plates, alternating with negative plates in a tank containing forming acid. The plates are then subjected to a charging current which is applied at a predetermined magnitude for a predetermined period of time. Another method of formation involves applying charging current to the completed battery. Using this formation process, groups of completed batteries, each containing electrolyte, are typically connected in series. A DC power supply is then electrically connected across the series connection of batteries, in order to apply a charging current of a predetermined magnitude for a predetermined period of time. The current magnitude and charging time depends on the characteristics of the battery being formed. Upon reaching the predetermined time and predetermined constant current, the plates of the batteries are considered to be fully formed.
In one commonly used technique, battery plates are formed using battery chargers having timers and current controls which are set by an operator to provide a predetermined amount of current for a predetermined period of time. The operator is required to determine the battery type, the required formation current and time, then set the charger accordingly. These settings, once made by the operator are assumed to be correct for the particular battery type. However, it has been found that the actual current applied as well as the time during which it was applied could vary considerably from that specified. Such variation can lead to excessive and unnecessary energy consumption.
In addition, using this technique, the operator is required to at least periodically monitor the temperature of the batteries in the formation area to insure that overheating does not occur. This leads to increased manufacturing costs due to the additional manpower required to perform the required monitoring.